1. Field of the Invention
The present invention generally relates to software framework planning and, more particularly, to a system and method for process planning and execution of separate phases of a plan in order to schedule and/or coordinate complex tasks on one or more computer systems.
2. Background Description
Planning systems have been a long-standing research topic, typically stemming from the field of artificial intelligence. As such, the output over the years has been planning systems that aim at high-level problem solving. That is, research in this area has mainly focused on the determination and inferencing of sub-goals and deducing activity that can produce those goals. Generally this is achieved using backward or forward chaining techniques as described in “Reasoning About Plans”, The Morgan Kaufman Series in Representation Reasoning, by Allen et al., 1991, Morgan Kaufman Publishers. Thus, planning systems have focused more on plan deduction rather than the actual management of the execution of the resulting plan.
Recent work has attempted to look at plan revision (see, “Applying Dynamic Planning Frameworks to Agent Goals” by Barber et al. AAAI, 1999). However, these attempts tend to solve the planning process as a central process, with the plan itself being a result of that process. Or, the planning revolves about goal-action inferencing techniques to re-plan execution at an agent level. In these attempts, the actual plan is an executable path towards some goal.
Other works on this subject include U.S. Pat. No. 5,329,626 to Klein et al. which is directed to a system and method for synchronizing portions of a distributed transaction. During the processing of a transaction, a number of agents are formed for handling various aspects or portions of the computations to be performed. Each agent progresses through a predefined set of state transitions which define the status of the agent at any point in time. The state transitions, in these agents, are dependent on the status of other ones of the cooperating agents. The computation management system of Klein et al. defines for each agent a set of dependencies, each dependency corresponding to one or more state transitions. By defining dependencies for each agent, Klein et al. is able to show how agents are interdependent, and set up necessary data structures to denote those interdependencies.
In U.S. Pat. No. 5,499,364 to Klein et al., as another example, a distributed computation system is provided which has a set of agents that perform each specified distributed computation. The event dependencies between events in the agents are dynamically specified at run time from a set of predefined dependency types. Each agent stores in its local knowledge database a representation of the conditions for local events, which are state transition events in that agent, and a representation of the conditions for those external events that depend on notifications of local events in this agent and for those external events on which the local events are dependent.
However, both of the Klein et al. references focus on how plan phases (agents) or external processes can cooperate through transactions. The issues of common state on conditions or blocking on state transitions are purely at the discretion of the plan phases (agents) themselves. What cannot be determine from the Klein et al. references, as well as other literature, are frameworks that address having the plan itself dynamically responding to changes and devising its own course of action.